Washington ? Disregard for voluntary rules intended to ensure the flow of electricity opened the way for last summer’s blackout in eight states and Canada, investigators said Monday in their final report. They urged government standards with teeth to ward off future outages.

There was a clear understanding long before the August blackout that the Ohio region where the problems began was highly vulnerable to grid instability, according to the report from a U.S.-Canada task force.

Had the situation been properly addressed, the cascading blackout that sped across states from Michigan to New York and into Canada probably would have been averted, the report concluded.

Something as simple as shutting off 200 megawatts of power an hour before the blackout might have kept the problem from spreading, investigators said.

But FirstEnergy Corp., the Ohio utility whose lines initially failed, had little understanding of its own power transmission system because it had not carried out the recommended long-term planning and safeguards — and backup monitoring system — that it needed, the report said.

Investigators said they found at least seven violations of industry-sponsored North America Electric Reliability Councilreliability rules linked to the blackout.

The U.S.-Canada Power System Outage Task Force, created to examine the nation’s worst blackout, urged creation of mandatory government reliability standards with penalties for those who violate them. The council, which issues the voluntary standards, has no enforcement authority.

It’s been eight months since the blackout, and Congress has yet to act on any measures that might improve grid reliability. Provisions to establish mandatory rules on the electricity industry have been caught up in a partisan fight over broader energy legislation.